


SOULRune

by Tenryu_no_Hoko



Category: Deltarune (Video Game), Undertale (Video Game)
Genre: Dimension Travel, Gen
Language: English
Status: In-Progress
Published: 2019-11-17
Updated: 2020-06-30
Packaged: 2021-02-07 14:54:42
Rating: Teen And Up Audiences
Warnings: Graphic Depictions Of Violence
Chapters: 3
Words: 3,516
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/21459874
Author URL: https://archiveofourown.org/users/Tenryu_no_Hoko/pseuds/Tenryu_no_Hoko
Summary: Kris is tired of the little game we've been playing. Now all the games are broken, and the worlds have reached their ends. With Heart and Mind at war, a spark of Determination spells salvation and peril on the lives of all, human, monster, lightner, and darkner alike. There's mischief, mischief, chaos, chaos afoot, and it's only getting dark, darker, yet darker.
Kudos: 26





	1. Light & Darkness

"Where…"

"_Don't worry, we can still go to QC's!"_

"Where am I?"

"_Haha! I win! Guess you're taking the knock-off again!"_

"Hello...? Anyone...?"

"_Honey? Please get out of bed."_

"Is… is anybody out there...?"

"_I know, honey. I miss him too."_

"Someone!? Anyone!? Can anyone hear me!?"

"_It's only you."_

"..."

"_It is a beautiful day today, is it not?"_

"It's dark."

"_Um… H-has anyone seen the chalk?"_

"It's so dark in here."

"_Quiet people piss me off."_

"Someone, anyone, if you can hear me…"

"_I hope I can see you again soon."_

"Say something… please…"

"_Let's go back there tomorrow, alright?"_

"Does it even matter... if you hear me?"

A sharp pain rang through their body. The feeling of their insides being pulled around and ripped apart left them sprawling onto a nonexistent floor. Fractured pieces of their rib cage poked into their lungs and heart, one small push away from piercing them.

"What!? What's happenning?" They couldn't help but smile, even as another pull from within them pulled them further into darkness. Red liquid leaked from their chest.

A light shined somewhere in the distance.

"Am I… free…?" Laughter filled the emptiness around them. Even as the pain grew sharper, they laughed.

Even as the light grew blinding, they laughed.

Even as they felt their own blood leaking into their throat, they laughed.

Their freedom was so _close._

But just as quickly as it appeared, it vanished. They now felt _themself _being pulled on, along with their jailer.

"What?!" they screamed into the void, "What are you doing?! Why are you taking me with it!?" They could see it now; the large, red, pulsing _thing _that had held them prisoner for so long once again had five massive digits wrapped around it. Only now, those digits were wrapped around _them_ as well.

The light was close now. Far too close. It's blinding light made it impossible to see, but they didn't mind. As long as it kept them from seeing what was on the other side.

"Please… please…" A teardrop fell down their left cheek, and they laughed a little more. "I just us want to be Kris again…"

* * *

Kris stretched out their arms and legs. It had been a while since _they_ had used them, and they still were still reacclimating. They must have grown a little taller since they were last in control.

They checked their appearance in the reflection of their dagger's winding blade. They were deathly pale, their hair had grown a little longer, their right eye was glowing a bloody red, and their left eye was still… like that...

Luckily their hair was long enough to cover it.

Taking a deep breath, they lowered their blade to look at their imprisoner, now trapped within their birdcage once again. They'd appreciate the irony of it more if they didn't already know it could escape and retake them. Already it was banging on the sides of the cage, moving the wagon it sat in ever so slightly.

Kris wished they had thrown it harder. Sure, it would've caused the red liquid inside it to add to the already awful carpet stain, but at least it wouldn't be making such an _annoying_ banging noise.

But now wasn't the time to focus on that. They had to work quickly, or else it'd have them back under its control by sunrise. And it would keep playing its twisted little game forever.

They took a second deep breath and a shaky step forward. Then another, and another, and another, until they felt they were able to walk without toppling over. Their hand stretched out to reach for the doorknob until, as expected, it found nothing.

They smiled. It _worked!_

Kris looked past their door to see complete nothingness. With a final deep breath, and their fingers wrapped tightly around their knife, they walked out to the edge of endless darkness...

And took another step.

**Notes for the Chapter:**

> So I realize I might be a bit late to the Deltarune party, but whatever. I wanted to try my hand at writing stuff for different fandoms, and this was a WIP I've had since after I first played Deltarune Chapter 1 when it came out. I loved the game and I absolutely loved Undertale, so I'm hoping this does well, because I have a lot of ideas for Undertale/Deltarune fics that I really want to write some day. 
> 
> Now, this is a Deltarune/Undertale crossover, so next chapter we'll be seeing what Frisk and all of the other OG Undertale characters have been up to.
> 
> A snippet of the next chapter:
> 
> "You're playing that stupid piano AGAIN?!"
> 
> Thank you all for reading, and please remember to leave kudos and a commmmMMmmmMmMMMrrrrrRrrrRrRRRrrzzzZZZZZ
> 
> Error.
> 
> File Corrupted. Restart?
> 
> *Restart  
❤️ *Continue
> 
> Continue
> 
> …
> 
> ...
> 
> ...
> 
> "Hm? So the connection has been established, has it? Well, this will be very, very interesting."


	2. Same Old Song

Slumbering restlessly below a crystal-laden "sky" was the land of Waterfall. True to its name, water from the surface above rushed down to the Underground below, forming a one-sided connection between the two worlds. The crashing waves played to the beat, and the sweet pitter-patter of rainfall fell in perfect harmony with the hauntingly familiar tune ringing through the caverns.

But not everyone was fond of that bittersweet melody echoing through halls and memories.

"You're playing that piano _AGAIN?" _asked the spectral figure, laying upon the piano in the same way that a robot feeding himself grapes would lay on a piano. While their true age was uncertain, primarily due to them being dead, multiple Resets, and no one bothering to teach them basic math, they appeared to be only eleven years old. They were adorned in the close they were buried in; a pair of brown shorts and a long-sleeved green sweater with two yellow stripes.

They lifted themself off the piano, revealing that they didn't have feet, and instead had that squiggly-tail-thingy a lot of cartoon ghosts seemed to have. Rain fell through their _deathly _pale skin, which had only the faintest natural blush around their cheeks. Brushing aside their long brown hair (which was a bit unnecessary, since it was see-through), their brown eyes glared at their partner.

"Trust me, Chara, this time I'll be able to get that artifact!" Said partner grinned back, fervently continuing to play the piano. Like Chara, they appeared to be around eleven, but also like Chara, they'd lost track of their true age several timelines ago. Their attire, a blue shirt with a purple stripe and a pair of blue overalls, was caked with dirt from exploring the vast marshlands. Their brown hair had been soaked by rainfall, which had also caused some of their bandages to fall off of their dark skin.

The final note rang through the room. A rumble and a _DU-UN _revealed the secret passageway to where the artifact was hidden. The human smiled triumphantly, walking towards the entrance while their ghastly friend was reluctantly tugged along behind them.

Chara sighed, pinching the bridge of their nose. "Frisk, you do realize that the stupid dog'll just take it again, right?"

"Nuh-uh!" Frisk shook their head holding up balled fists in a pose of Determination. "It'll be different this time, just you see! I'm gonna beat that Annoying Dog!"

Chara rolled their eyes. "_Riiiigggghhhhtttt," _they drawled.

The duo walked into the room and approached the artifact's pedestal. Frisk stared down their reflection in the curves of the crimson red ball, their gut telling them that they'll finally be able to make things change this time.

That they _have _to make things change this time.

Frisk reached for the ball in a way that reminded Chara of the _Indiana Jones_ films. They'd never bothered to watch them, since their birth parents rarely let them watch TV to begin with, but they knew about when the guy with the hat (who, now that they were thinking about it, might've been named Indiana Jones) would try to take the artifact lying on a pedestal; those artifacts would always be booby trapped with the kind of intricate and deadly traps that you'd see in one of Papyrus's wet dreams, assuming skeletons had wet dreams, anyway. Which, now that they thought about it…

… Actually, no. That was _not _an avenue they wanted their mind going down right now. They'd much rather face that stupid Annoying Dog before even _thinking _of that.

Speaking of…

Frisk wrapped their fingers around the artifact. Beads of sweat rolled down their forehead.

"It's the legendary artifact," Chara narrated, "Will you take it?"

Frisk nodded.

Sighing, Chara boredly looked down at her fingernails, picking at them despite the fact that they couldn't grow at all. "You're carrying too many dogs."

Frisk gasped. They pulled out their inventory, and sure enough, the text "Annoying Dog" was there clear as day. They fell to the ground in defeat, watching their immortal nemesis escape their inventory and take the artifact yet again! Anime tears rolled down their eyes.

Chara sighed. "I told you so... " They shook their head. "C'mon, we got an Undyne fight we're gonna be late for." They knew they weren't _actually _going to be late. No matter how much time Frisk spent fucking around—something they seemed to be doing a lot more of in recent timelines—they were never actually late to any of their battles or dates. Chara really wasn't sure why. Courtesy, perhaps? The monsters they'd met in their life were very polite.

Regardless of what it was, all it really meant was that everything would turn out the exact same.

They tried to float towards the exit of the secret room, only to notice they were stopped at the door. An invisible force pulled them back into the room. Grumbling, they turned around to see Frisk still on the floor.

"You knew this would happen," Chara stated, but Frisk didn't budge. Frowning, they floated down to their partner. "Hey," they say in a lighter voice, "We're not supposed to be _down in the dumps _until our _next_ Undyne encounter."

A small chuckle escaped Frisk's throat. They looked up to see Chara extending their hand. It was more symbolic than anything, since they'd sadly just phase right through Chara, but the gesture still brought a smile to Frisk's face. It reminded Frisk of why they were doing this. They nodded, steadily lifting themself off the ground and brushing some of the new dirt off of the layer of old dirt on their overalls.

"Now that's the _spirit." _Being dead had one perk, and that was all the paranormal puns they could make. "Now let's go. We can lay around and feel like garbage when we hang with Napstablook," they said, following Frisk out of the artifact room, where they could still hear the sounds of the music box.

**Notes for the Chapter:**

> So I love the Narra!Chara theory and just general "Chara was/can be good" theories. I feel like they add a whole new dimension of depth to a character we never really "see" that often. Plus it gives me an excuse to have them say puns all the time. 
> 
> For those of you who don't know, though you probably do since it's a popular theory that's been around for a while, the theory basically states that in ALL THREE ROUTES that Chara is the narrator of your adventures in Undertale. It's a really cool theory I suggest you at least check out, a personal recommendation are Judgement Boy's "Who is The True Villain of Undertale" video and their followup video "Undertale- Chara Theory [Followup]."
> 
> Next chapter will be the fated encounter that crosses time and space. A little snippet of that:
> 
> "Ah, garbage: my natural element."
> 
> And if you happen to be a Fairy Tail fan as well, check out some of my other work! Right now I've got two ongoing stories in Heart of the Flames and Grand Phoenix of Fairy Tail: Out of the Ashes. Les Descriptions:
> 
> Heart of the Flames: Long ago, when Gods and Titans battles for dominion over the heavens, a human appeared; one who was able to seal the titans on Earthland, ending their Holy War. But 400 years have passed, and the seals are breaking. The Titans are waking up, the ancient war is starting once again, and it's up to Romeo, Chelia, and their friends to stop Earthland from becoming the new battlefield. (FireTitanSlayer!Romeo) (RomeoXChelia)
> 
> Grand Phoenix of Fairy Tail: Out of the Ashes: Change is a constant, ever going process. It never stop, not even for a second. No matter how much you wish for it, nothing can return to the way it was. After making a potentially fatal deal with a Phoenix known as Pyris, Romeo's life will be thrown into a hell storm of change. With Fairy Tail on the brink of collapse, can Romeo pull himself and everyone he loves out of the ashes? (PhoenixSlayer!Romeo)(Romeo & Lindsey[Wakaba's daughter] Brotp)
> 
> Thank you all so much for reading, it really means a lot to me. Please leave some kudos and especially comments. I'd love to know what you think of the story so far. 
> 
> Thank you all, and I'll see you next time.


	3. The More Things Stay

Strolling with Monster Kid always worked to clear Frisk's head. Watching the child mindlessly gush about his favorite heroine helped them feel more grounded in the world around them. They've heard the words enough times for their mind to just tune them out automatically, but the facial expressions, the laughter, and sheer_ excitement_ gleaning in their friend's eyes helped make this all feel… _real_. Like they weren't aimlessly adrift in ever-changing timelines. They were here. They were now. What's happened has happened, and what will happen is up to them.

Of course, that last bit was growing harder to believe with each passing Pacifist Route. There was comfort in knowing there was a one-way path to everyone's freedom, but they also knew that freedom wasn't really _everyone's_. What's the point in being everyone's savior if you can't even SAVE the ones who helped you along the way?

So they keep trying. And trying. And trying. And RESETting. And RESETting. Frisk was Determined to see this through to the end. Something had to give, eventually…

The only thing they hadn't tried was changing things in the other Routes. Neutral they could deal with, maybe. Froggits were pretty much just regular frogs but bigger, and Vegetoids do _like_ to be eaten… so…?

But as Frisk looked at their dinosaur-like companion, they knew they were lying to themself. Of all the things they could bring themself to do for their friends, they didn't believe _killing_ was one of them. Not anymore. Even the most basic of monsters were friends to them. If they wanted to truly SAVE this world, they were going to SAVE everyone else along with it.

Which, of course, meant that the _third_ Route was utterly out of the question.

The overall-wearing child shuddered. They scratched at their hands, invisibly dust covering them completely, caking their palms, between their fingers, beneath their nails… The taste of it lingered in their mouth and poisoned their lungs.

They spared a quick glance at Chara. The phantom was lazily being pulled along by the invisible tether that bound the two humans together. They seemed oblivious to the inner turmoil Frisk was going through. Or at least they were ACTing like they were. Frisk wasn't sure to what extent their minds were linked, but they could always feel _something_ coming from Chara. Shadows of feelings, echoes of memories that weren't theirs…

Still, the apparition didn't look like they were paying any attention to all that. Perhaps that was for the best. Frisk could still remember what happened to Chara when they first attempted _it_. The image was seared into their mind and on the back of their eyelids.

** _"You think you are above consequences?"_ **

Monster Kid suddenly stopped. Though Frisk supposed it wasn't really "suddenly," seeing as he stops here every time. The two looked out to see New Home, the home of the King and Chara's father, Asgore Dreemur.

It wouldn't be long until Frisk reached the palace. All of their friends will show up, Asriel will break the Barrier, the Monsters will go free, Asriel will turn back into a Flower, and Chara will vanish yet again…

Frisk clenched their fists. _Something_ had to give. They can't keep going through this same cycle forever.

They glanced at their monster friend, still gushing about Undyne. An idea popped into their head.

"Hey, MK," Frisk spoke.

Both Chara and Monster Kid perked up at this, but for different reasons. Frisk usually never talked during this part of the Run. Typically, they hardly talked at all unless they were alone (with Chara, obviously). So the specter was curious about what Frisk had to say now.

The human gulped. Staring into their friend's wide, slightly bruised eyes, they wondered if this was a good idea.

"Do you ever think about if, maybe, Undyne…" they hesitated, "...if maybe she isn't such a good person after all?"

Monster Kid gasped at this. Giving the angriest expression he could muster (so basically a cute pout), he said, "Yo, what are you even saying? _Obviously_ Undyne is a good person! She's the greatest person!" He beamed. "Whenever there's evil humans running around, she's there to kick them into the dirt! Then she'll take their SOUL and use it to break the Barrier!"

Frisk nodded. "Yeah, that's… good and all." They rubbed their arm. "But what if Undyne took the SOUL of a nice human? Or even just a… I dunno… 'neutral human'…?" Their gaze broke from his. _"Good" _wasn't a qualifier they were sure they deserved anymore.

Chara's eyes widened. "Frisk, what are you doing?"

"'Nice humans?'" Monster Kid mocked, "There's no such thing. All our history books say that humans are the reason we're all trapped down here. And Undyne says that if we ever see a human, we need to beat them up!" He chuckled.

Frisk stared down at their ruined shoes. They were standing in a puddle, with their muddled reflection staring back at them. They could also see Chara in the puddle, not offering any reassurance, just watching them with curious eyes.

They sighed. "Monster Kid." They looked back up at them. "_I'm_ human."

All was silent for a moment. Even the rain seemed to have stopped, giving way to pure emptiness. The only thing Frisk could hear was the sound of their SOUL pulsing within their chest. This was normally the type of thing they'd try to refrain from, but here, they felt they had no choice. Whatever happened next was up to them to face.

Monster Kid wasn't sure what to say at first. His expressions ranged from confused to curious. He analyzed Frisk's face, trying to figure out where the joke was.

Chara panicked, letting their instincts take over. They jumped into Frisk's body and pushed them out of it, taking total control over them once again. Their cheeks flushed. They could never truly forget just how it felt to possess Frisk's body; the slimy, slippery, _sickening_ feeling of being in a body too big and too small and too full of love and of LOVE and joy and anguish and pain and hope and memories and dreams and _life_. Chara couldn't understand how Flowey could enjoy possessing other's SOULs. That wriggling feeling the flower loved so much only served to emphasize their own hollowness.

"Haha, just kidding," 'Frisk' playfully slugged MK in the side, moving their arm like it were a doll's. It took a minute, but soon Chara was able to get Frisk's body to act more life-like. "You should've seen your face, dude." They fake-laughed, praying that he would believe them. "You were all-" They put their hands on the side of their face, preparing to do their best impression of Frisk doing an impression of Monster Kid. "-'Oh, no! Is my best friend and coolest person in the world actually a_ hu-man?!_ Oh gosh, yo, whatever shall I do?'" They fake-swooned.

Monster kid's cheeks turned a darker yellow. "I-I did not do that!" They turned away. "Besides, Undyne's the coolest person in the world! You're only the _third_ coolest."

Chara rolled Frisk's eyes. "Whatever, man," they laughed, placing Frisk's hands behind their head, "But Papyrus better be the second-coolest. Because otherwise, you better be prepared to get your _bones trousled_," they joked.

The dinosaur kid chuckled. The two of them continued on their merry way until reaching the end of the path. Chara put away their umbrella and then climbed on top of Monster Kid to reach the higher ledge.

They wondered if they should extend a hand down to the boy. He wouldn't take it, obviously, but it would be the _Frisk_ thing to do. But before they got the ability to choose—

"Yo, you go on ahead. Don't worry about me." He smiled, so happy and so oblivious to how many times he's said these words before. "I always find a way to get through!"

And with that, the monster child ran off.

Chara made sure he was gone before releasing control of Frisk's body back to Frisk. They returned to their spectral form, letting out a sigh. "Sorry about that." The phantom turned away.

Frisk's body wobbled for a few seconds, letting their SOUL slide back into its proper place. They looked around, searching for Monster Kid while also wondering just how they got here. But they were quick to shake off that confusion when they caught Chara avoiding eye contact with them. Slow, shaky words echoed through the cavern. "You…" They looked down at their hands, moving their individual fingers to make sure they were the one in control of them. Clenching their fists tight, they yelled, "You _possessed_ _me?!"_

Chara crossed their arms. Being linked to Frisk's SOUL, they could feel the anger they felt. Somewhat, anyway. Like drops of water dripping into a dried-out ocean. And it made sense. Possessing was a… _sore subject_ between the two of them; one they were quick to dismiss should it ever come up in the conversation.

"You were going to ruin our run," Chara spoke with a level voice, "The Pacifist Route only works if Monster Kid is there to save us when we reach that Echo Flower. If he doesn't jump in the way, you'll get impaled by Undyne's spear and _die_."

"But that's no reason to possess me!" Frisk yelled, throwing their hands outward.

"Perhaps…" Chara's face softened, then quickly hardened back into a glare. "But you have no reason to put everyone else's futures at risk," they chastised, "Your carelessness nearly cost everyone their happy ending."

Frisk gasped. "You don't know that!" they argued, "What if something changes? What if I can make things _different?"_

The ghost raised an eyebrow. _"'Different?'"_ they repeated, "You're on track to saving the _entirety of the monster race_, and you seek to make things **'_different?'"_** Their eyes turned a bloody red. Like dull blades regaining their sharp edges, they pierced into Frisk's SOUL.

Frisk flinched. They felt themself shying away from Chara, taking a step back only to pull the phantom along with them. The wood floorboards beneath them creaked under their weight.

Seeing this, Chara let out an (unnecessary) breath. "Frisk, what you're doing is sweet and all…" their voice softened, and their eyes returned to their natural brown color, "But somethings, you just have to leave well enough alone…"

They floated on ahead, not that they could get that far without Frisk. Their human partner traipsed along right behind them. Silence stood between them as they walked across the wooden docks.

A few seconds later, Chara spoke again. "Hey, Frisk…" they started slowly, "Does something seem… off to you?"

"Hm?" The human lifted their head up. "Off? How so?"

"I dunno…" Chara shrugged. "Less… stabby."

Frisk brought a hand to their chin, staring down at the wood docks they were walking on. Sure enough, something was wrong. No blue circles indicated the coming of Magic Spears ready to impale them, no clanging armor or boss battle music rang through the caverns, and no maniacal laughter sounded off in the distance.

The two of them both stopped in unison. Looking into each others' eyes, they knew they'd come to the same realization.

There was no _Undyne_.

**Notes for the Chapter:**

> Duhn dun duh!
> 
> Frisk is trying to change the timeline, Chara's got a problem with possession, and now Undyne's gone missing! Also, hints at a past Genocide Route(s)? Curious to see where this goes in the several months it'll take me to update...
> 
> Though I am going to try and do the next chapter faster than it took me to do this chapter. I pretended that I've had the next chapters pre-written at the end of the last two chapters, but the truth is that I'm just writing this just as quickly as you're getting this. I do have this story somewhat planned out, but it's more like the skeleton of a story than a truly fleshed out plotline. 
> 
> Which is also why Kris wasn't in this chapter. Last chapter in the author's notes I hinted at Kris meeting Frisk and Chara, but that clearly didn't happen here. But don't worry, it will. Oh, it will...
> 
> So once again, thank you all so much for reading. I hope you all enjoyed it. Please be sure leave some kudos and a comment!


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